Railway signaling system



Nov. 10, 1942. s YOUNG 2,301,493

RAILWAY SIGNALING SYSTEM Filed Jan, 25, 1942 2 Sheets-Sheet l Fil lWT/ZNTOR H0010 5. 160129' Y HIS ATTORNEY Nov. 10, 1942. H s YOUNG RAILWAY sIGNALING SYSTEM Filed Jan. 26, 1942 2 Sheets-Sheet 2 g. MAQ mm W o y M wm fw. mp A n P 5 HW. w @w my RM NL Patented Nov. 10, 1942 RAILWAY SIGNALING SYSTEM Henry S. Young, Wilkinsburg, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a. corporation of Pennsylvania Application January 26, 1942, Serial No. 428,219

5 Claims.

My invention relates to a railway signaling system of the type shown in Letters Patent of the United States No. 1,822,497 issued September 8, 1931, to H. S. Loomis, and employing traincarried governing means adapted to cooperate with train controlling devices located in the trackway.

Signaling systems of this type have inductors located at the entrance of each track section. Each inductor has a U-shaped core having a winding thereon while the inductors cooperate with train-carried equipment so that if at the time the train passes over an inductor the cir-` cuit of the winding of the inductor is open the train-carried equipment will operate to apply the brakes, while if at the time the train passes over an inductor the winding of. the'inductor is short circuited the train-carried equipment is not affected.

It is customary in systems of this kind to arrange the wayside apparatus so that Vthe circuit of the winding of the inductor for each track section is controlled in accordance with the aspect displayed by the wayside signal for that section in such manner that the winding of the inductor is short circuited when the signal displays its clear indication and is open circited at all other times.

It has heretofore been proposed to check the circuits of the inductor windings by including each winding in the pick-up circuit of the relay which causes the associated wayside signal to display its clear indication. This prevents the display of a clear indication by a signal if the circuit of the winding of the associated inductor is defective and thus prevents an emergency application of the brakes on a train when the train passes theinductor associated with a signal displaying a clear indication.

The systems heretofore provided have been arranged so that one terminal of the inductor winding is permanently connected to one of the line wires over which energy is supplied from the adjacent signal in advance to the relay which controls the clear signal indication. This wire may also serve as the common wire for other circuits and may be grounded so that if a cross to ground develops with the wire leading from the other terminal of the inductor winding the inductor winding will be short circuited regardless of whether the relay controlling the clear signal indication is energized or not. If this condition develops and a train should pass the inductor at a time when the associated signal is displaying its stop or its caution indication the 55 train-carried equipment will not function to apply `the brakes.

It is an object of this invention to provide a signaling system of the type described and incorporating improved means to control the circuits of the inductor windings.

A further object of the invention is to provide a system of the type described which is arranged so that when the track relay for a section is released the circuit of the winding of the inductor for that section is isolated from the signal control circuits to thereby minimize the possibility that this winding will be improperly short circuited.

Another object of the invention is to provide an improved system ot the type described which is arranged so that the circuit of the winding of the inductor for each section is checked-just prior to passage of a train over the inductor to thereby minimize the possibility that a defect'will develop in thecircuit of the inductor winding between the time the circuit is checked and the time at which a train passes over the inductor.

Other objects of the invention and features of novelty will be apparent from the following description taken in connection with the accompanying drawings.

I shall describe three forms of railway signal*- ing systems embodying my invention, and shall then point out the novel features thereof i claims.

In the drawings Fig. 1 is a diagram of a stretch of railway track equipped with a signaling apparatus embodying my invention, and

Figs. 2 and 3 are diagrams showing modifications which I may employ.

Similar reference characters refer to similar parts in each of the several views.

Referring to Fig. l of the drawingsthere is shown therein a stretch of track having track rails i and 2 over which trafiic normally moves in the direction indicated by the arrow, that is, from left to right. The rails of the track stretch are divided by insulated joints 3 into the customary track sections for signaling purposes. These sections are designated 3T, 4T, and 5T. Each section is provided with a track circuit consisting of a track battery connected across the section rails at the exit end of the section, and a track relay, designated TR. with an appropriate prex, connected across the section rails at the entrance end of the section.

Each track section has at the entrance end thereof a suitable wayside signal designated S with a suitable prefix. These signals may be of any appropriate type and as shown in Fig. 1 are of the semaphore type, and each is capable of displaying a proceed, a caution, and a stop indication. Each signal has associated therewith a contact 25 which is governed in accordance With the position of the semaphore arm. Each such contact is arranged so that the contact is open when the semaphore arm is in its horizontal or stop position, and is closed when the arm is in its 45 or caution position or its 90 or clear position, or is intermediate its caution and clear positions.

Each signal has associated therewith a relay TP and a relay D Which cooperate as explained below to control the signal-and to control the supply of energy to the adjacent signal in the rear. Each signal also has associated therewith a battery M, while the negative terminal C of each battery is connected to a common line wire I which extends throughout the track stretch.

Each track section is provided with an inductor K which is located in the trackway a short distance Vin the rear of the entrance end of the section. Each inductor is vadapted to cooperate in the usual manner with train-carried apparatus of any appropriate design. The train-carried apparatus is not a part of this invention and has not been shown in order to simplify the disclosure.

The equipment is shown in the con-dition which it assumes when the track stretch is vacant. As the stretch is vacant the track relays are picked up. As relay ETR is picked up the circuits of the relays TP and 5D are complete and the relay ETP is energized `over the circuit which is traced from terminal B of the battery 5M, wire Il, contact I2 of relay 5TH., contacts E4 and l5 of relay 5D `in multiple, contact i6 of relay 5TH, winding of relay ETP, and a branch of Wire it! to terminal C of battery 5M.

As relay STP is energized its contact 2e estab lishes the circuit of relay 5D to permit energy to be supplied to this relay from the battery associated with the adjacent signal in advance.

In addition, contact 22 of relay ETP is closed and establishes connection from Wire il to wire 29 so that energy is supplied to the caution operating circuit of the signal 5S.

. As relay 4D is energized energy is supplied to the clear operating circuit of signal 5S to cause the semaphore arm of this 'signal to remain in its vertical position to provide the proceed or clear indication. The circuit for supplying energy to the signal is traced from terminal B of the battery 5M through front contact 22 of relay tiTP, wire 29, front contact 23 of relay 5D, wire 2d, signal 5S and a branch of wire it to terminal C of the battery 5M.

As the signal 5S is displaying its clear or proceed indication signal operated contact 25 is closed and energy from the battery 5M is supplied to the relay 4D over the circuit which is traced kfrom terminal B of the battery through wire il, signal Contact l25, front contact 2l of relay ETP, wire 28, front contact `2B 'of relay FSTP, Winding ci relay 4D, and common wire lil to terminal C of the battery 5M.

As the contacts of relay 5D are picked up, its contacts I4 and :l5 short circuit the Winding of 'the inductor 5K as is obvious from the drawings.

.fir

of traiiic passes through the track stretch the locomotive carried apparatus will not be ailected by the inductors 2K and 5K as the windings of these inductors are short circuited.

When the train enters section 5T track relay @TR releases and its contacts l2 and l5 interrupt the circuit of the relay 4T? so that contact 25 of relay 5T? interrupts the circuit of Irelay iiD, while contact El of relay lTP interrupts the supply of energy to the wire 2S leading to the adjacent signal in the rear and contact 22 of relay TP inten rupts the supply of energy to the caution and clear operating cir-cuits of signal dS so that this signal displays its stop indication. As relay D is deenergized its contacts M and i5 release and open the circuit short circuit-ing the Winding of inductor K.

Accordingly when section 4T is occupied signal iS displays its stop indication, While the winding of inductor 41K is open circuited so that the traincarried apparatus on a following train will cause the brakes on the train to be applied if the train passes over the inductor.

When the train advances into section 5T the signal for this section is placed at stop and the winding of the inductor 5K is open circuited, while the supply of energy to wire 23 leading to signal iD is cut on".

When the train vacates section iT track relay Tl-"t picks up and a circuit including the winding of inductor [iK in series therewith is established to energize the relay llTP. This circuit is traced from terminal B of battery 11M through wire Il, front Contact t2 of relay iTR, Winding of inductor 6K, contact l5 of relay 4TH, winding of relay 61T?, and wire itl to terminal C of the battery. Accordingly, if the circuit of the inductor winding is complete the relay TP will be energized in series with this winding, but if the cir-cuit of the inductor winding is defective the relay 4T? will remain released.

When the relay STP picks up its Contact 22 establishes connection from terminal B of the battery 4M to the caution operating wire 29 for signal dS and this signal displays its caution indication while contact 25 is closed so that connection is established from terminal B of battery PQM to wire 28 leading to the adjacent signal in the rear. As contact 2t of relay iTP is picked up energy may be supplied to relay iiD, but as long as section 5T is occupied energy is not supplied to the Wire 23 leading to relay D andfthis relay remains released.

At this time the terminals or the winding of the inductor @K are connected together through the winding of relay iTP and the battery ftlVl, but the resistance of this connection is so high that the inductor functions as though its circuit were open, and if a train passes over the inductor the train-carried apparatus will operate to apply the brakes unless it is suppressed b-y the engineer.

When the train vacates section 5T the equipment for this section operates in the same manner as that for section fl-T and relays ETR and STP pick up while energy is supplied to the caution operating circuit for signal 5S, and contact 2l of relay ETP and signal operated contact 25 establish connection from terminal B or" battery iM to wire 2S leading to relay dD. Accordingly, the contacts of relay iD become picked up and its contact 23 establishes the clear or proceed operating circuit for the signal 13S so that the signal displays its proceed indication while contacts id and I5 of relay D short circuit the Winding of the inductor 4K so that train-carried equipment will not be affected by the inductor.

On picking up of the contacts of relay 4D and short circuiting of the Winding of the vinductor 4K the current to energize the relay 4TP is supplied through contacts I4 and l5 of relay 4D instead of through thev Winding of the inductor.

If at the time the train vacates section 4T the circuit of the Winding of the inductor 4K is defective, the relay 4TP will not be energized and its contacts Will remain released and will not establish the caution operating circuit of the signal 4S and this signal will continue to display its stop indication. In addition, as signal 4S is at stop and relay ITP is released energy is not supplied to wire 28 leading to the adjacent signal in the rear and that` signal continues to display its caution indication.

Furthermore,v as relay 4TP is deenergized when the circuit of the Winding of the inductor 4K is defective, the circuit of the relay 4D is interrupted and this relay remains released when section T is vacated and energy is supplied to line Wire 28 leading to the relay 4D.

It will beseen, therefore, that the system shown in Fig. 1 is arranged so that the circuit of the Winding of the inductor for a section is checked every time a train passes through the section, and if the circuit of the inductor Winding is defective, the signal for the section Will continue to display its stop indication after the section is vacated while the adjacent signal in the rear will display its caution indication.

Accordingly, -a signal cannot display an indication inconsistent With the condition of the associated inductor, and a defective inductor cannot produce an unexpected application of the brakes on passage of a train over the inductor at a time when the associated signal is displaying its clear or proceed indication.

In addition, it will be seen that the system is arranged so that when the contacts of the relay D are released the circuit of the winding of the associated inductor is isolated from the signal circuits and a ground onone of the Wires leading from the inductor Winding cannot result in short circuiting of an inductor Winding.

In Fig. 2 of the drawings there is shown a modification which I may employ in place of that shown in Fig. l. This modification is similar to that shown in Fig. l, butdiifers therefrom as a repeater relay is provided for the distant signal control relay and this repeater relay checks the circuit of the inductor winding. v

The equipment of Fig. 2 is shown in the condition which it assumes when the track stretch is vacant. At this time the track relays are picked up and contact 33 of each track relay establishes the circuit through which energy is supplied over the Wires 23 to the relays DR. Accordingly the contacts of the relays DR are picked up and their contacts 3| and 32 establish the circuit to energize the associated relay DP from the battery M at that location. The circuit for energizing the relay 4DP is traced from terminal B of the battery 4M through front contact 3| of relay 4DR, contacts 34 and 35 of relay 4BP in multiple, contact 32 of relay 4DR, and winding of relay 4Dn to terminal C of the battery 4M.

As the contacts of the relay Dl? are picked up, the Contact 3l of each relay establishes the clear or proceed operating circuit for the associated signal and the signal displays its proceed indication, While its contact establishes connection from terminal B of the associated battery to the wire 28leading tothe adjacent signal finA the rear.

In addition, theV contacts 34 and 35 cf each relay` DP short circuit the Winding of the associated inductor K so that a train may pass over the inductor without delay.

When a train moving in the normal direction of trailic, that is, from left to right, enters section 4T track relay 4TR releases and its contact 38 interrupts both the caution and proceed operating circuits for the signal 4S, while its contact 39 interrupts the circuit of wire 28 leading to the adjacent signal 'in the rear. The signal 4S, therefore, displaysits stop indication and its contact`25 is opened to additionally interrupt the circuit of the wire 28. On release Vof track relay 4TR its Contact 30 interrupts the circuit of relay 4DR so that contacts 3| and 32 of relay 4DR release and interrupt the circuit of relay 4BP. Accordingly, the contacts of relay 4BP release and its contact 31 additionally interrupts the clear operating circuit of the signal While contacts 34 and 35 of the relay interrupt the circuit short circuiting the winding of the inductor 4K.

p On entrance of the train into section 5T track relay ETR releases and causes release of relays 5DR and 5DP`, While the signal 5S goes to stop.

When the train vacates section 4T track relay 4TR picks up and its contact 33 establishes the cautionv operating circuit of the signal 4S and this signal displays its caution indication, While its contact 25 is closed and cooperates with front contact 33 of relay 4TR to supply energy to the Wire 28 leading to the adjacent signal in the rear.

At this time contact 30 of relay 4'I'R is closed to permit energy to be supplied to relay 4DR, but as sgnal 5S is at stop and relay STR is released energy is not supplied to Wire 28 leading to relay 4DR and this relay remains released and interrupts the circuit of relay 4BP. Accordingly, relay 4DP remains released and its contact 31 interrupts the clear or proceed operating -circuit of the signal 4S, While contacts 34 and 35 of relay 4DP continue to interrupt the circuit short circuiting the winding of the inductor 4K.

When the train vacates section 5T track relay lEiTlR. picks up and its contact 38 establishes the caution operating circuit for signal 5S and signal controlled contact 25 closes and cooperates with contact 39 of relay 5'IR to establish connection from terminal B of battery 5M to Wire 28 leading to relay 4DR. Accordingly, energy is supplied from battery 5M over Wires 28 `and I3 to relay 4DR and the contacts of this relay pick up so that energy is supplied from battery 4M to relay 4DP ,over the circuit which is traced from terminal B through front contact 3| of relay 4DR, winding of inductor 4K, front contact 32 of relay 4DR, winding of relay ADP, and Wire IB to terminal C.

If the circuit of the inductor winding is intact, the relay 4DP will be energized in series With the inductor Winding and the contacts of relay 4D? Will pick up so that contact 3'! establishes the clear operating circuit for signal 4S, while lcontacts 34 and 35 short circuit the Winding of inductor 4K and establish connections shunting the inductor winding for energizing the Winding of relay 4BP. The signal 4S, therefore, displays its clear or proceed indication while the circuit of the inductor Winding is short circuited.

If, at the time the train vacates section 5T and the contacts of relay 4DR. 4pick up, the circuit of the Winding of the inductor 4K is defective, en-

ergy will not be supplied tothe winding of the relay SDP and the contacts of this relay will remain released so that the clear operating circuit of the signal S is not established and the signal continues to display its caution indication, and contacts Sii and 35 of relay ADP do not short circuit the winding of the inductor 4K. Accordingly, a following train will receive a caution indication from signal iS while the inductor 4K will vcause an application of the train brakes.

It will vbe seen, therefore, that the system shown in Fig. 2 is arranged so that the circuit of the winding of the inductor associated with each section is checked every time a train passes through the track section, and if the Winding is defective the associated signal cannot be conditioned to display its clear indication.

The modincations shown in Pigs. 1 and 2 are arranged so that the circuit of the winding of each inductor is checked immediately after pa.,- sage of a train, and if a defect in an inductor winding develops after the circuit of the winding has been checked it will not be discovered until after the passage of another train.

The modiiication shown in Fig. 3 is similar to that shown in Fig. 2, but differs therefrom as it is arranged so that the circuit of the Winding of the inductor for each section is checked immediately before entrance of a train into the section.

The modification shown in Fig. 3 employs a searchlight signal of the type shown in Letters Patent of the United States No. Re. 14,940 issued to E.. J. Blake, While this modification employs an approach relay AR which governs the circuit of the lamp L of the associated signal and also governs the circuit of the relay DP. Each signal includes a contact Y which is operated by the signal mechanism and controls the circuit of the relay AR so that this relay may be energized when the signal is conditioned to provide its yellow indication and is deenergized when the signal displays its red or its green indication.

The equipment is shown in the condition which it assumes when the track stretch is vacant. At this time the track relays TR are picked up and the relays EAR and ADR are energized in series over the circuit which is traced from terminal B of battery 5M, wire Il, Winding of relay EAR, `front contact Y of signal 5S, front contact 39 of relay 5TH, wire 28, front contact 3S of relay QTR, Winding of relay dDR, and wire I3 to terminal C of the battery 5M. Accordingly, the contacts of relay EiAR are `picked up and its contact ll interrupts the circuit of the lamp L of signal 5S, while its contact il? interrupts the circuit of the relay 5DP so that the contacts of this relay are released and its contacts 36 and 3l cause the energy supplied to the operating winding of the signal `5S to be of the polarity effective to cause the signal to display its yellow or caution indication. The circuit for supplying energy to the signal winding is traced from terminal B of the battery 5M through wire ll, front contact 38 of relay ETR, back Contact Cil of relay `SDP, winding of the signal, back contact 35 of relay EDP, and wire I to terminal C.

As the relay 4DR is energized its contacts 3l and `32 are closed to permit energy to be supplied to the relay DP, but at this time the supply of energy to this relay is interrupted by contact 42 of relay dAR so relay DP remains released and its contacts 34 and 35 do not short circuit the winding of the inductor 5K, while its contacts 3S and 3l cause the energy supplied to the operating winding of signal "is to be of the polarity effective t0 Cause the .signal to display its caution indication.

At this time relay EDR. is energized in series with the approach relay for the section in ad- Vance, while the relay AR is energized over a circuit similar to that traced for relay EAR.

When a train moving from left to right enters section 3T the track relay, not shown, for this section releases and its contact 33 interrupts the circuit for energizing the relay EAR in series with the relay 3DR, not shown. Accordingly, the relay llAR releases and its contact fl! establishes the circuit of the lamp L of signal 5S, while its Contact l2 establishes the circuit to energize relay DP in series with the winding of the inductor lili. This circuit is traced from terminal B of battery QM, through wire H, back contact l2 of relay llAR, front contact 3l of relay 4DR, winding of inductor 5K, front contact 32 of relay 4DR, winding of relay DP, and wire It to terminal C of the battery.

If the circuit of the inductor winding is intact, the relay DP will be energized in series with the inductor winding and the contacts of the relay will pick up and short circuit the inductor winding and establish a path shunting the inductor winding for energizing the relay winding. In addition, on picking up ofthe relay contacts its contacts 395 and change the polarity of the energy supplied to the winding of signal iS so that the signal is conditioned to display its green or clear indication.

On this change in the aspect of the signal contact Y of the signal is opened and interrupts the circuit of the approach relay @AR to insure that this relay remains released and maintains the circuit of the relay liDP.

If at the time the train enters section 3T and relay AR releases the circuit of the winding of inductor 4K is defective, the relay DP will remain released and its contacts Sli and 31 will maintain the supply of energy to the signal winding of the polarity effective to cause the signal to provide its yellow or caution indication, while contacts S and 35 of the relay do not short circuit the inductor winding. Under these conditions, therefore, the train approaching signal 4S will receive a caution indication from this signal, while the inductor K will cause the traincarried apparatus to provide a brake application unless it is suppressed by the engineer.

When the train advances into section liT track relay STR releases and its Contact 35i interrupts the circuit for energizing the relays BDR and 5AR in series, and the relay EAR releases to establish the circuit of the lamp L of signal 5S, and to also establish the circuit for energizing the relay SDP in series with the winding of inductor 5K so that this relay changes the polarity of the energy supplied to the winding of the signal 5S to thereby cause this signal to provide its green or clear indication, while contacts 3@ and 353 of relay 5DP short circuit the inductor 5K.

In addition, on release of track relay GTR. its contact 39 interrupts the circuit for energizing the relay flAR in series with the relay DR, not shown, associated with the adjacent signal in the rear. This insures that the relay MR will remain released and maintain the circuit of the lamp L of signal 4S. Release of contact 3B of track relay TR interrupts the supply' of energy to the operating winding of signal iS so that the signal displays its red or stop indication.

Release of contact St of relay dTR interrupts the circuit of relay GDR, as explained above, and

contacts 3l and 32 of this relay interrupt the circuit of relay 4DP so that the contacts 34 and 35 of this relay remain released so that the winding of the inductor 4K is open circuited, while contacts 36 and 31 of relay 4DP are released so that on subsequent picking up of the track relay contacts the energy supplied to the operating winding of the signal 4S is of the polarity effective to cause the signal to display its yellow or caution indication.

Y Similarly, when the train enters section 5T and track relay 5'IR releases relays SAR. and 4DR are maintained released, while the supply of en- ,ergy to the winding of the signal 5S is interrupted sc that the signal displays its stop indication. In addition, release of relay ETR interrupts the circuit of the relay BDR and the contacts of this relay release and interruptV the circuit of the relay SDP.

When the train vacates section 3T the track relay, not shown, for that section picks up, but at this time the circuit of relay 4AR is also interrupted by contact 3S of relay 4TR so relay IAR remains released and maintains the supply oi energy to the lamp L of signal 4S.

When the train vacates section 4T track relay 4TR picks up and its contact 39 completes the circuit for energizing the relay 4AR in series with the relay DR of the adjacent signal in the rear. Accordingly, the relay 4AR picks up and its contact 4| interrupts the vcircuit of the lamp L cf signal 4S, While contact 42 prevents the supply of energy to the relay ADP.

In addition, on picking up of the contacts of track relay 4TR its contact 38 establishes the circuit for supplying energy to the winding of the signal 4S. At thistime the contacts 3E and 3l of relay 4BP are released so that the energy supplied to the signal winding isiof the polarity effective to cause the signal, when lighted, to display its yellow or caution indication.

AOn picking up of the contacts cf track relay 4TRits contact 30 is closed'to permit energy to be supplied to the relay 4DR. At this time, however, section 5T is occupied and relay ETR is released so that its contact 39 interrupts the circuit of the relay 4DR andthis relay remains-released and prevents energization of the relay 4BP.

It will be seen, therefore, that when a section is vacated the lamp of the signal for that section is extinguished, while energy is supplied to thefwinding of the signal to condition it when lighted to display its yellow or caution indication. In addition at this time relays DR and DP remain released so the inductor winding is open circuited.

Accordingly,`if while section 5T is occupied, a second or following train enters section 3T, the track relay for this section will release and interrupt the circuit of relay AAR so that this relay releases and its contact 4l establishes the circuit of the lamp L of signal 4S. This signal, therefore, will display its yellow or caution indication.

On release of relay 4AR its contact 42 closes, but at this time relay 4DR is released, as explained above, so energy is not supplied to relay ADP and this relay remains released so the winding of the inductor 4K is open circuited, and if the train passes over the device the brakes on the train will be applied unless prevented by the engineer from doing so.

If the second or following train enters section 4T, track relay TR will release and interrupt the supply of energy to the winding of signal 4S so that this signal displays its red or stop indication.

. On release of track relay ITR its contact 30 interrupts `the circuit for energizing'relays 4DR -and 'SAR in'series, but this circuit is already interrupted by contact 390i relay STR and by contact Yoiv signal 5S so opening of 'Contact `3ll` of relay 4TR is without eifect.

When the rst train vacates section 5T the equipment associated with this section operates in the same manner as that associated with section 4T so that energy is supplied to the winding of the signal 5S to condition it when lighted to provide its yellow or caution indication.

As track relay STR is picked up and as the contact Y of the signal 5S' isclosed, and assuming section 6T to be unoccupied, the circuit for energizing the relays EAR and 4DR in series is established and the contacts of these relays pick up. On picking up of the'v contacts of relay SAR its contact 4| interrupts the circuit of the lamp L of signal 5S, while on picking up of the contacts of relay 4DR its contacts3l and 32 are closed to permit energy to 'be supplied to relay 4DP on subsequent release of the contacts of relay 4AR.

From the foregoing it will be seen that the modification shown in Fig. 3 is arrangedso that the relays DP which control the green or'clear signal indications also control the circuits of the inductor windings. It will be seen also'that the energy to pick up the contacts of the relays DP is supplied through the inductor windings so that these relays will not pick up to change the signal aspect from caution to clear unless the circuits Vof the inductors are intact. y

In additiom-iti will be seenvthat the circuit of the relay DP for eachsignal is governed by the approach relay for that signal so that the relay DP for each section is released until the adjacent section in the rear is occupied. Y Accordingly, the circuitof the winding of the inductor for each section is checked immediately prior to passage of a train over the inductor. This substantially eliminates the possibility that adefect will develop in the circuit of the inductor winding subsequent to picking up of the relay DP and prior to the passage of a train over the inductor.

It will be seen also that the modication shown in Fig. 3 is arranged so that when the contacts of the relay DP are released the wires leading to the winding of the associated inductora-re isolated from the signal control circuits so that a defect in these circuits will not result in short circuiting of the inductor winding.

Although I have herein shown and described only threeforms of railway signaling systems embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:` y

-1.In a railway signaling system, in combination, a section of railway track, a signal at the entrance of said section capable of displaying a. stop and a proceed indication, a trackway device at the entrance of said section adapted to cooperate with train-carried apparatus, said trackway device having a core and a winding, a relay, a source of current, means for connecting one terminal of the winding of said relay to one terminal of said source, means governed by traffic conditions in said section for connecting the other terminal oi the relay winding to one terminal of the winding of the trackway device and for connecting the other terminal of the winding of the trackway device to the otherV terminal of said source, means effective when said relay is energized to condition said signal to provide its prostop and a proceed indication, la trackway device i at the entrance of said section adapted to cooperate with train-carried apparatus, said trackway device having a core and having a winding having a iirst and a second terminal, a relay effective when energized to condition the signal to provide its proceed indication, said relayhaving a normally released movable contact whichwhen the relay winding is energized is moved into engagement with a stationary contact, the winding of the trackway device having one of its terminals connected to one ci said relay contacts and having its other terminal ccnnected to the other relay contact, a source oi current, means for connecting one terminal of the winding of said relay to one terminal of said source, and means governed by traic Yconditions in said section for establishing connection -irom the other terminal of the relay winding to the first terminal of the winding of said trackway device and for establishing connection from the second terminal oi the winding of said trackway device to the other terminal oi said source.

8. In a railway signaling system, in combination, a section of railway track, a signal at the entrance of said section capable of displaying a `stop and a proceed indication, a trackway device at the entrance of said section adapted to cooperatel with train-carried apparatus, said track- ,way device having a core and having a winding having a first 4and a second terminal, a relay ei- -lective when energized to condition the signal to provide its proceed indication, said relay having a normally released movable contact which when the relay winding is energized is mov-ed into engagement with a stationary contact, the winding of the trackway v device having one of its terminals connected to one of said relay contacts and having its other terminal connected to the other relay contact, a source of current, means `for connecting one terminal of the winding oi said relay to one terminal of said source, and means governed by traffic conditions in said section and in the adjacent section in advance for establishing connection from the other terminal of the relay winding to the rst terminal of the Winding of said trackway device and for establishing connection from the second terminal of the winding of said trackway device to the other terminal of said source.

4. In a railway signaling system, in combination, a forward and a rearward section of track, a signal at the entrance end of said rearward c e indication, a trackway device at the entrance or said rearward section adapted to cooperate with train-carried apparatus, said trackway device having a core and a winding, a rst and a second relay, means eective when said forward and rearward sections are both vacant to supply energy to said first relay, the second relay having a movable contact which when picked up engages a stationary contact, the winding oi the trackway device having one of its terminals connected to one contact of said second relay and having its other terminal connected to the other contact of said second relay, a source of current, means for connecting one terminal of the winding oi said second relay to one terminal of said source, a contact of said rst relay being effective when the relay is energized to connect the other terminal of the winding of the second relay to one terminal of the winding of the trackway clevice, another contact of said rst relay being efiective when the relay is energized to connect the other terminal of the winding of the trackway device to the other terminalV of said source, and means eiective when said second relay is energized to condition said signal to provide its proceed indication.

5. In a railway signaling system, in combination, a forward and a rearward section of track, a signal at the entrance end of said rearward section capable of displaying a stop and a proceed indication, a trackway device at the entrance of said rearward section adapted to cooperate with train-carried apparatus, said track way device having a core and a winding, a first and a second relay, means effective when said forward and rearward sections are bothvacant to supply energy to said first relay, the second relay having a movable contact which when picked up engages a stationary contact, the winding of the trackway device having one of its terminals connected to one contact of said second relay and having its other terminal connected to the other contact of said second relay, a source of current, means for connecting one terminal `oi the winding of said second relay to one termin-al of said source, a contact of said rst relay being effective when the relay is energized to connect the other terminal of the winding of the second relay to one terminal of the winding of the trackway device, another Contact of said rst relay being effective when the relay is energized to connect the other terminal of the winding of the trackway device to the other terminal of said source, means effective when said second relay is energized to condition said signal to provide its proceed indication, and means effective when the section in the rear of said rearward section is vacant to interrupt the circuit of said second relay.

section capable of displaying a stop and a pro- HENRY s. YOUNG. 

